Shingles Vaccine Significantly Reduces Serious Heart-Related Events in Individuals with Existing Heart Disease, New Research Reveals at ACC.26

Individuals living with established heart disease who received a shingles vaccine demonstrated a nearly 50% reduction in the rate of serious heart-related events within one year compared to their unvaccinated counterparts. These compelling findings, derived from extensive research, are being presented at the American College of Cardiology’s Annual Scientific Session (ACC.26), a premier global gathering for cardiovascular professionals dedicated to advancing heart health through scientific discovery and education. The study underscores a potentially profound cardioprotective benefit of the shingles vaccine, extending its utility beyond its primary role in preventing herpes zoster.

Major Reduction in Cardiovascular Risk Uncovered

The large-scale study, which analyzed data from over 246,822 adults across the United States, focused specifically on patients diagnosed with atherosclerotic heart disease. This condition, characterized by the accumulation of plaque within the arteries, is a leading cause of heart attacks, strokes, and peripheral artery disease, making these individuals a particularly vulnerable population. The research revealed that vaccinated individuals experienced a 46% lower likelihood of a major adverse cardiac event (MACE) – a composite endpoint often including heart attack, stroke, or cardiovascular death – and a remarkable 66% lower risk of all-cause mortality within the observed timeframe. Furthermore, specific event rates saw substantial decreases: the risk of heart attack dropped by 32%, stroke by 25%, and heart failure by 25% among those vaccinated against shingles.

Dr. Robert Nguyen, a resident physician at the University of California, Riverside, and the study’s lead author, emphasized the magnitude of these results. "This vaccine has been found over and over again to have cardioprotective effects for reducing heart attack, stroke, and death," Dr. Nguyen stated. "Looking at the highest risk population, those with existing cardiovascular disease, these protective effects might be even greater than among the general public." He further likened the observed reductions in cardiovascular risk to the significant health benefits achieved by quitting smoking, highlighting the critical impact this simple preventive measure could have.

Atherosclerotic Heart Disease: A Global Health Challenge

Atherosclerotic heart disease represents a monumental public health burden worldwide. It is the underlying cause of most cardiovascular diseases, which collectively remain the leading cause of death globally, accounting for an estimated 17.9 million lives each year according to the World Health Organization. In the United States alone, approximately 18.2 million adults aged 20 and older have coronary artery disease, the most common type of heart disease. Risk factors include high blood pressure, high cholesterol, diabetes, obesity, smoking, and a sedentary lifestyle. For individuals already diagnosed with this condition, managing existing risk factors and preventing secondary cardiovascular events is paramount, making any additional protective measure, such as vaccination, incredibly valuable.

Understanding Shingles and Its Connection to Cardiovascular Health

Shingles, medically known as herpes zoster, is caused by the reactivation of the varicella-zoster virus (VZV), the same virus responsible for chickenpox. After an initial chickenpox infection, VZV lies dormant in nerve cells for decades. It can reactivate, particularly in older adults or those with weakened immune systems, causing a painful rash, typically on one side of the body or face. This rash can lead to severe, long-lasting nerve pain called postherpetic neuralgia (PHN), which can persist for months or even years. The Centers for Disease Control and Prevention (CDC) recommends the shingles vaccine for all healthy adults aged 50 years and older, and for younger adults (age 19 and older) who are immunocompromised.

The mechanism by which shingles infection might increase cardiovascular risk is an area of active research. Previous studies have indicated that an active shingles infection can trigger a systemic inflammatory response, leading to endothelial dysfunction – damage to the inner lining of blood vessels – and promoting the formation of blood clots. This inflammatory cascade can significantly elevate the risk of acute cardiovascular events such as heart attacks and strokes, particularly in the weeks and months following the shingles outbreak. For instance, research published in the Journal of the American Heart Association has shown a transient but significant increase in the risk of stroke and myocardial infarction (heart attack) following shingles, with the highest risk observed in the first few weeks after infection. By preventing the shingles infection, the vaccine is hypothesized to avert this inflammatory response and subsequent pro-thrombotic state, thereby reducing the likelihood of these dangerous clotting events and their cardiovascular consequences.

A Deeper Look into the Study’s Methodology

To execute this comprehensive analysis, researchers leveraged TriNetX, a vast federated research network that aggregates de-identified electronic medical records from millions of Americans across numerous healthcare organizations. This robust database allowed for the examination of a large, diverse cohort of adults aged 50 years or older with atherosclerotic disease, encompassing data collected between 2018 and 2025.

The study meticulously matched two groups: 123,411 individuals who had received at least one dose of a shingles vaccine (either Shingrix or Zostavax, though Shingrix is now the preferred vaccine due to its higher efficacy and longer duration of protection) and an equal number of unvaccinated individuals. Crucially, the researchers employed sophisticated statistical methods to ensure both groups were highly comparable in terms of critical demographic factors (such as age, sex, race, and ethnicity) and pre-existing health conditions (comorbidities like diabetes, hypertension, dyslipidemia, and chronic kidney disease). This rigorous matching process was vital for minimizing confounding factors and strengthening the attribution of observed benefits to the vaccine itself.

The primary focus of the analysis was on heart-related outcomes that occurred between one month and one year after vaccination for the vaccinated group, and within a similar timeframe for the unvaccinated control group. This specific window allowed for the assessment of immediate to medium-term protective effects, while minimizing the influence of very short-term variations immediately post-vaccination.

Broader Implications for Public Health and Clinical Practice

The findings from this study carry substantial implications for public health policy and clinical practice. Given the high prevalence of atherosclerotic heart disease and the availability of a safe and effective shingles vaccine, these results provide a compelling additional reason for eligible individuals to consider vaccination. Public health organizations, including the CDC and American Heart Association, are likely to reinforce existing vaccination recommendations, potentially even elevating the discourse around the shingles vaccine as a tool for cardiovascular risk reduction.

For clinicians, particularly cardiologists and primary care physicians, these data offer a powerful talking point when discussing preventive care with their at-risk patients. Incorporating shingles vaccination into routine preventive health screenings for patients over 50, especially those with pre-existing cardiovascular conditions, could become an even more emphasized component of comprehensive care plans. The economic implications are also noteworthy; preventing costly and debilitating cardiovascular events through vaccination could lead to significant healthcare savings, reducing hospitalizations, rehabilitation costs, and the societal burden of long-term disability.

Dr. Nguyen underscored the broader societal value of vaccines, especially in an era marked by misinformation. "Vaccines are one of the most important medicines we have to prevent disease," he remarked. "Sometimes patients are unsure about whether they should get a vaccine or not, particularly in an age of disinformation. These results provide another reason for them to elect to get the vaccine." This statement highlights the role of robust scientific evidence in counteracting vaccine hesitancy and promoting informed health decisions.

Acknowledging Limitations and Charting Future Research

While the study presents robust evidence, the authors diligently acknowledged certain limitations inherent in observational research. A key consideration is the potential for "healthy user bias." Individuals who choose to receive vaccinations may also be more health-conscious overall, engaging in other beneficial behaviors such as regular exercise, a balanced diet, and adherence to prescribed medications. Although the researchers made significant efforts to adjust for various health and socioeconomic factors – including issues related to housing, economic circumstances, social environment, employment status, education, and literacy – it remains possible that some unmeasured confounders could still influence the observed benefits.

Despite this, the study’s immense sample size and the sophisticated statistical matching employed provide strong evidence for a genuine association between shingles vaccination and a meaningful reduction in heart risk. Future research could explore these potential confounders more deeply through prospective studies or by examining genetic predispositions that might influence both vaccine uptake and cardiovascular health outcomes.

Another limitation noted was the analysis tracking outcomes only during the first year after vaccination. While this provides crucial short-term data, the long-term effects warrant further investigation. However, previous research, such as a study published in 2025, offers encouraging signs, linking shingles vaccination to a 23% reduction in cardiovascular events in generally healthy adults, with benefits potentially lasting up to eight years. This suggests that the protective effects may extend well beyond the initial year, providing sustained benefits. Longitudinal studies that track vaccinated individuals for several years would be invaluable in confirming the durability of these cardioprotective effects in high-risk populations.

Dr. Nguyen is scheduled to present the full study, titled "Herpes Zoster Vaccination and Risk of Cardiovascular Events in Patients with Atherosclerotic Cardiovascular Disease," on Monday, March 30, at 12:30 p.m. CT / 17:30 UTC in the Posters, Hall E section of ACC.26. The presentation is anticipated to generate considerable discussion among the cardiovascular research community, further solidifying the growing understanding of the far-reaching benefits of routine vaccination. This research adds a compelling chapter to the narrative of preventive medicine, positioning the shingles vaccine not just as a defense against a painful rash, but as a potential ally in the ongoing battle against heart disease.